WO2017217538A1

WO2017217538A1 - Drawn body for automobile structural member, method for manufacturing drawn body for automobile structural member, and apparatus for manufacturing drawn body for automobile structural member

Info

Publication number: WO2017217538A1
Application number: PCT/JP2017/022346
Authority: WO
Inventors: 研一郎大塚; 隆司宮城
Original assignee: 新日鐵住金株式会社
Priority date: 2016-06-16
Filing date: 2017-06-16
Publication date: 2017-12-21
Also published as: CN109311513A; KR20190008566A; EP3473530B1; MX2018015402A; US10913102B2; RU2705881C1; US20190176211A1; CN109311513B; EP3473530A4; CA3026400A1; JPWO2017217538A1; KR102196701B1; EP3473530A1; BR112018075251A2; JP6687110B2

Abstract

This drawn body for an automobile structural member is configured so that the tensile strength thereof is 980 MPa or more, two first protruding ridge lines, a second protruding ridge line, and a recessed ridge line thereof each have a radius of curvature of 30 mm or less, the corner radius of each corner wall is 30 mm or less, and the forming depth, which is the distance between a top panel and an outward flange, is 40 mm or more.

Description

Drawing member for automobile structural member, method for producing drawing member for automobile structural member, and apparatus for producing drawing member for automobile structural member

The present invention relates to a drawn molded body for automobile structural members, a method for producing a drawn molded body for automobile structural members, and an apparatus for producing a drawn molded body for automobile structural members.
This application claims priority on June 16, 2016 based on Japanese Patent Application No. 2016-120157 for which it applied to Japan, and uses the content here.

As automobile structural members, for example, long members having a hat-shaped cross-sectional shape such as side sill, bumper reinforcement, A pillar lower panel, A pillar, and B pillar are widely used. As a material of these automobile structural members, for example, a thin high-strength steel sheet having a plate thickness of 1.4 mm or less and a tensile strength of 980 MPa or more is used from the viewpoint of reducing the weight of the automobile and improving the collision safety. Yes.
On the other hand, a reduction in bending rigidity and torsional rigidity (hereinafter collectively referred to as “rigidity”) of the vehicle body (body shell) has become a problem due to thinning of automobile structural members. For this reason, the improvement of the rigidity of the automobile structural member obtained by pressing a thin high-strength steel plate is strongly calculated | required.

Since the formability of high-strength steel sheets is low, automobile structural members made of thin high-strength steel sheets are generally formed by press working by bending. However, when the above-described long automobile structural member is formed by press working by bending, shrinkage tends to occur in the flange-formed part during bending.

Therefore, these automobile structural members cannot have a structure having an end wall at an end portion in the longitudinal direction (a structure in which a cross-sectional shape perpendicular to the pressing direction is U-shaped or rectangular). For this reason, it must be a hat-shaped open cross-sectional structure composed of a top plate portion, side walls adjacent to both sides of the top plate portion, and flanges adjacent to the side walls.

The rigidity of an automobile structural member having a hat-shaped open cross-sectional shape is lower than the rigidity of an automobile structural member having a U-shaped cross-sectional shape or a rectangular cross-sectional shape. Even if an automobile structural member having a U-shaped cross-sectional shape or a rectangular cross-sectional shape can be formed, the forming depth should be reduced in order to avoid the occurrence of wrinkles on the end walls and side walls. Inevitably, an automobile structural member having high rigidity cannot be obtained.

As described above, when the above-described automobile structural member is manufactured using a thin high-strength steel plate having a tensile strength of, for example, 980 MPa or more as a raw material, the plate thickness is thin and the forming depth is shallow. An automobile structural member having high rigidity cannot be manufactured.

In Patent Document 1, when a press tool for forming a metal plate into a cross-sectional hat shape is performed using a processing tool having a punch, a die, and a wrinkle presser, both ends in the width direction of the metal plate are formed by the die and the wrinkle presser. First, using a punch having a semicircular convex section on the head that is convex toward the metal plate in a state where the metal plate is sandwiched and pinched, the punch is applied to the metal plate portion that forms the hat-shaped wall section. The metal plate is subjected to pre-processing for forming a convex shape in which the convex portion of the metal plate is brought into contact and the hat head portion of the metal plate is convex outward, and then the predetermined cross-section is applied to the pre-processed metal plate. There has been disclosed a press working method excellent in shape freezing property, characterized by using a punch for obtaining a hat shape and performing a finishing process.

Patent Document 2 discloses a method of manufacturing a polygonal annular member from a metal flat plate by press working, and includes a flat portion, a corner portion formed of a curved surface, and a deformed portion in a boundary region between the corner portion and the flat portion. A step of forming a side peripheral portion formed by drawing, a step of forming the side peripheral portion to a predetermined height from the metal flat plate surface, and the annular member over the height of the side peripheral portion. The corner portion is pushed out from the inside and the metal material forming the deformed portion is replenished to the edge portion, so that the curvature from the corner portion is smaller than the radius of curvature of the corner portion on the inner peripheral surface of the annular member. A method of manufacturing a polygonal annular member including the step of forming the edge portion having a radius is disclosed.

Japanese Unexamined Patent Publication No. 2004-181502 Japanese Unexamined Patent Publication No. 2011-245502

In the invention disclosed in Patent Document 1, since the top plate portion of the molded product by preliminary processing is crushed by finishing, the radius of curvature of the bent portion in the cross-sectional view can be reduced, but the corner radius in plan view is set. It cannot be made smaller.

In the invention disclosed by patent document 2, in order to use the tool pressed from the inside of the corner portion in the step of forming the edge portion, it is necessary to remodel the equipment such as a mold and the remodeling content becomes complicated. Equipment costs increase.

The present invention has been made in view of the above circumstances, and it is possible to provide a drawing molded body for an automobile structural member and a drawing molded body for an automobile structural member capable of enhancing impact resistance characteristics by increasing the rigidity while realizing weight reduction. It is an object of the present invention to provide a manufacturing method and an apparatus for manufacturing a drawn molded body for automobile structural members.

The present invention is as listed below.

(1) A first aspect of the present invention is an automotive structural member drawn molded body having a tensile strength of 980 MPa or more, and the top plate portion extending in the first direction and the top plate portion in the first direction. Two first convex ridge lines that are orthogonal and adjacent to both sides in the second direction along the top plate, and the two first convex ridge lines that are adjacent to the extreme end of the top plate in the first direction. A second convex ridge line part continuous to the part, two side walls adjacent to the two first convex ridge line parts, an end wall adjacent to the second convex ridge line part, the two side walls, and the end wall Two corner walls having a shape that is curved when viewed from a direction orthogonal to the first direction and the second direction, and a recess adjacent to the two side walls, the end wall, and the two corner walls. A ridge line portion and an outward flange adjacent to the concave ridge line portion.
The two first convex ridge line portions, the second convex ridge line portion, and the concave ridge line portion each have a radius of curvature of a cross section perpendicular to the extending direction of 30 mm or less, and the outward flange and the concave ridge line A corner radius, which is a radius of curvature of the square wall as viewed from a direction orthogonal to the first direction and the second direction, at a position 1.0 mm away from the boundary with the portion along the square wall is 30 mm or less. The forming depth, which is the separation distance between the top plate portion and the outward flange in the direction perpendicular to the top plate portion, is 40 mm or more.

(2) In the drawn molded body for automobile structural member according to (1), the end wall, the two square walls, the concave ridge line portion, and the outward flange are formed at both ends in the first direction. Also good.

(3) The drawn molded body for an automobile structural member described in the above (1) or (2) may be a side sill, a bumper beam, an A pillar lower panel, an A pillar, or a B pillar.

(4) A second aspect of the present invention is a method for producing a drawn article for an automobile structural member according to any one of (1) to (3) above, in a blank having a tensile strength of 980 MPa or more, By performing press forming by drawing using a first die, a first punch and a first blank holder, an intermediate top plate portion extending in the first direction and the intermediate top plate portion orthogonal to the first direction. Two intermediate first convex ridge line portions adjacent to both sides in the second direction, and an intermediate second adjacent to the outermost end portion in the first direction of the intermediate top plate portion and continuous to the two intermediate first convex ridge line portions. A biconvex ridge line portion, two intermediate side walls continuous to the two intermediate first convex ridge line portions, an intermediate end wall adjacent to the intermediate second convex ridge line portion, the two intermediate side walls, and the intermediate end Adjacent to the wall and directly in the first direction and the second direction Two intermediate corner walls having a curved shape when viewed from the direction in which they are bent, the two intermediate side walls, the intermediate end wall and the intermediate concave ridge line portion adjacent to the two intermediate angular walls, and adjacent to the intermediate concave ridge line portion An intermediate outward flange, and the two intermediate first convex ridge line portions, the intermediate second convex ridge line portion, and the intermediate concave ridge line portion each have a curvature radius of a cross section orthogonal to the extending direction. A radius of curvature of a section perpendicular to the extending direction of each of the two first convex ridge line portions, the second convex ridge line portion, and the concave ridge line portion of the drawn molded body, and the intermediate outward flange and the An intermediate corner that is a radius of curvature of the intermediate angle wall viewed from a direction orthogonal to the first direction and the second direction at a position spaced 1.0 mm along the intermediate angle wall from the boundary with the intermediate concave ridge line portion Radius is the aperture An intermediate forming depth, which is a separation distance between the intermediate top plate portion and the intermediate outward flange in a direction perpendicular to the intermediate top plate portion, which is larger than the corner radius of the corner wall of the shape, is the draw formed body. A first step of forming a first intermediate drawn body that is larger than the forming depth, and press working by drawing using the second die, the second punch, and the second blank holder on the first intermediate drawn body. And reducing the curvature radius of the cross section perpendicular to the extending direction and the intermediate forming depth of the two intermediate first convex ridge line portions, the intermediate second convex ridge line portion, and the intermediate concave ridge line portion. By the second, the second first ridge line part, the second convex ridge line part and the concave ridge line part of the drawn molded body have a radius of curvature of the cross section perpendicular to the extending direction and the molding depth. Intermediate drawing A second step of forming a body, and the second intermediate drawn body is constrained by the second die, the second punch, and the second blank holder, with an inner pad incorporated in the second punch. While pressing the inner surface of the intermediate end wall of the first intermediate drawn molded body, the intermediate corner radius of the intermediate angular wall is pressed by the tightening tool against the intermediate end wall of the second intermediate drawn molded body in the first direction. And a third step of reducing the size of the drawn structure.

(5) In the method for manufacturing a drawn article for an automobile structural member according to (4), the intermediate molding depth is 1.1 to 2.0 times the molding depth, The radius of curvature of each of the one convex ridge line part, the intermediate second convex ridge line part, and the intermediate concave ridge line part is the curvature of each of the two first convex ridge line parts, the second convex ridge line part, and the concave ridge line part. The radius may be 1.2 to 30 times, and the intermediate corner radius may be 1.2 to 30 times the corner radius.

(6) In the method for manufacturing a drawn article for an automobile structural member according to (4) or (5), the tightening tool may be arranged to be movable in the first direction outside the second die. Good.

(7) In the method for manufacturing a drawn member for an automobile structural member according to (4) or (5), the tightening tool is arranged to be movable in the first direction from the outside to the inside of the second die. May be.

(8) A third aspect of the present invention is the apparatus for manufacturing a drawn article for an automobile structural member according to any one of (1) to (3), wherein the first die, the first punch, and A first molding die having a first blank holder, a second die, a second punch, and a second molding die having a second blank holder, and a tightening tool, wherein the first molding die is By pressing a blank with tensile strength of 980 MPa or more by drawing, adjacent to the intermediate top plate portion extending in the first direction and both sides of the intermediate top plate portion in the second direction orthogonal to the first direction. Two intermediate first convex ridge line portions, an intermediate second convex ridge line portion adjacent to the end portion in the first direction of the intermediate top plate portion and continuous to the two intermediate first convex ridge line portions, and Two intermediate side walls continuous with the two intermediate first convex ridge lines, and the intermediate An intermediate end wall adjacent to the two convex ridge lines, the two intermediate side walls, and adjacent to the intermediate end wall, and having a curved shape when viewed from the direction orthogonal to the first direction and the second direction. Two intermediate corner walls, the two intermediate side walls, the intermediate end wall and an intermediate concave ridge line portion adjacent to the two intermediate angular walls, and an intermediate outward flange adjacent to the intermediate concave ridge line portion, The two intermediate first convex ridge line portions, the intermediate second convex ridge line portion, and the intermediate concave ridge line portion each have a radius of curvature of a cross section perpendicular to the extending direction, and the two second convex portions of the draw-formed body. It is larger than the radius of curvature of the cross section orthogonal to the extending direction of each of the one convex ridge line part, the second convex ridge line part and the concave ridge line part, and from the boundary between the intermediate outward flange and the intermediate concave ridge line part, 1.0mm along the middle corner wall The intermediate corner radius, which is the radius of curvature of the intermediate corner wall viewed from the direction orthogonal to the first direction and the second direction, is greater than the corner radius of the corner wall of the drawn molded body, A first intermediate drawing body in which an intermediate forming depth, which is a separation distance between the intermediate top plate portion and the intermediate outward flange, in a direction perpendicular to the intermediate top plate portion is larger than the forming depth of the draw forming body; The second molding die is formed by press-molding the first intermediate drawn molded body by drawing, and the two intermediate first convex ridge line portions, the intermediate second convex ridge line portion, and the intermediate concave ridge line portion. By reducing the radius of curvature of the cross section orthogonal to each extending direction and the intermediate molding depth, the two first convex ridge line portions, the second convex ridge line portion, and the concave ridge line of the drawn molded body are reduced. Part of it Forming a second intermediate drawing body having a curvature radius of the cross section perpendicular to each extending direction and the forming depth; and the tightening tool is configured to form the second intermediate drawing body into the second molding die. The intermediate end wall of the second intermediate draw-molded body is pressed against the first end while pressing the inner surface of the intermediate end wall of the first intermediate draw-formed body with the inner pad incorporated in the second punch. It is a manufacturing apparatus of the drawing molded object for motor vehicle structural members which makes it press in a direction and makes the said intermediate corner radius of the said intermediate corner wall small.

(9) In the apparatus for manufacturing a drawn article for an automobile structural member described in (8) above, the intermediate molding depth is 1.1 to 2.0 times the molding depth, and the two intermediate The curvature radii of the first convex ridge line part, the intermediate second convex ridge line part, and the intermediate concave ridge line part are respectively the curvature radii of the two first convex ridge line parts, the second convex ridge line part, and the concave ridge line part. The intermediate corner radius may be 1.2 to 30 times, and the intermediate corner radius may be 1.2 to 30 times the corner radius.

(10) In the drawing apparatus for automobile structural members described in (8) or (9) above, the tightening tool is arranged to be movable in the first direction outside the second die. Also good.

(11) In the drawing apparatus for automobile structural member described in (8) or (9) above, the tightening tool is arranged to be movable in the first direction from the outside to the inside of the second die. May be.

According to each of the above aspects, the tensile strength is 980 MPa or more, the molding depth is deep, the curvature radius of the ridge line portion and the corner radius of the square wall are small, and the end wall has an end wall in the longitudinal direction. It is possible to provide a drawn molded body for an automotive structural member that can improve collision resistance characteristics by increasing rigidity while realizing weight reduction.

It is explanatory drawing which shows typically a part of drawing molded object for motor vehicle structural members which concerns on one Embodiment of this invention. It is explanatory drawing which shows typically the drawing molded object for motor vehicle structural members in the case of having an end wall in both ends. It is explanatory drawing which shows the state before joining this side sill to A pillar lower panel, when using the drawing molded object for motor vehicle structural members which concerns on this embodiment as a side sill. It is explanatory drawing which shows the 1st example of the aspect which joins a side sill to an A pillar lower panel. It is explanatory drawing which shows the 2nd example of the aspect joined to a side sill and an A pillar lower panel. It is explanatory drawing which shows the 1st intermediate | middle draw-molding body shape | molded by a 1st die | dye, a 1st punch, and a 1st blank holder. It is explanatory drawing which shows the 1st step from a 1st intermediate | middle draw-molded body through a 2nd intermediate | middle draw-molded body to manufacture a draw-formed body. It is explanatory drawing which shows the 2nd step until it manufactures a drawing molded object through a 2nd intermediate | middle drawing molded object from a 1st intermediate | middle drawing molded object. It is explanatory drawing which shows the 3rd step until it manufactures a drawing molded object through a 2nd intermediate | middle drawing molded object from a 1st intermediate | middle drawing molded object. It is a top view sectional drawing which shows the molding condition in case the cam is arrange | positioned out of the 2nd die | dye over time. It is side surface sectional drawing which shows a shaping | molding condition in case the cam is arrange | positioned out of the 2nd die | dye with time. It is explanatory drawing which shows a shaping | molding condition in case the cam is arrange | positioned in a 2nd die | dye with time. It is explanatory drawing which shows the to-be-tested object A used in the Example. It is explanatory drawing which shows the to-be-tested object B used in the Example. It is explanatory drawing which shows the to-be-tested body C used in the Example. It is explanatory drawing which shows the to-be-tested object D used in the Example. It is explanatory drawing which shows the to-be-tested object E used in the Example. It is explanatory drawing which shows the to-be-tested object F used in the Example. It is explanatory drawing which shows the to-be-tested object G used in the Example. FIG. 6 is an explanatory diagram showing measurement conditions for torsional rigidity with respect to a device under test A. 5 is a graph showing the evaluation results of torsional rigidity for test objects A to G. It is explanatory drawing which shows the measurement conditions of the bending rigidity with respect to the to-be-tested object A. 3 is a graph showing the evaluation results of bending rigidity for test objects A to G.

As a result of intensive studies in order to solve the above-mentioned problems, the present inventor produces a drawn article having a tensile strength of 980 MPa or more, a radius of curvature of a target ridge line portion, a corner radius of a corner wall, and a molding depth. In order to achieve this, the present inventors have found that it is effective to employ the following steps (a) to (c), and have further studied and completed the present invention.
(A) Using a 1st shaping | molding metal mold | die, the curvature radius of a ridgeline part and the corner radius of each wall are shape | molded larger than target value, and it is set as a 1st intermediate | middle drawing molded object.
(B) Using a second molding die, the first intermediate drawn body is formed into a second intermediate drawn body having a cross-sectional shape having a curvature radius and a forming depth of a target ridge line portion.
(C) Using a tightening tool such as a cam, the longitudinal end of the second intermediate drawn body is pressed in the axial direction of the second intermediate drawn body, and the corner radius of the square wall is reduced.
Hereinafter, embodiments of the present invention based on the above-described knowledge will be described with reference to the drawings.

(1. Drawing 1 for automobile structural members according to an embodiment of the present invention)
FIG. 1 is an explanatory view schematically showing a part of the structure of a drawn body 1 for automobile structural members (hereinafter simply referred to as “drawn body 1”) according to the present embodiment.

The draw-formed body 1 is a cold or warm draw-formed body made of a high-tensile steel plate having a plate thickness of 0.7 to 3.2 mm and a tensile strength of 980 MPa or more.
The plate thickness is preferably 0.8 to 1.8 mm, and more preferably 0.8 to 1.4 mm.
The tensile strength is preferably 1180 MPa or more, and more preferably 1310 MPa or more.
The upper limit value of the tensile strength of the high-tensile steel plate is preferably 1800 MPa in order to ensure practicality.
As shown in FIG. 1, the drawn molded body 1 includes a top plate portion 2, a first convex ridge line portion 3, a second convex ridge line portion 4, a side wall 5, an end wall 6, a square wall 7, a concave ridge line portion 8, and an outward direction. It is constituted by a flange 9.

The top plate part 2 has a substantially planar shape and extends in a first direction d1 indicated by a double arrow in FIG. The top plate part 2 does not need to be a flat surface and may be curved. The two first convex

ridge line portions

3 and 3 are in the second direction d2 which is the width direction of the top plate portion 2 (the direction indicated by the double arrows in FIG. 1 and orthogonal to the first direction d1 and the top plate portion 2 Are formed continuously on both sides.

The second convex ridge line portion 4 is adjacent to the outermost end portion 2a in the first direction d1 of the top plate portion 2, and is formed continuously with the two first convex

ridge line portions

3 and 3. The two

side walls

5 and 5 have a shape along a plane and are formed adjacent to the two first convex

ridge line portions

3 and 3, respectively. The end wall 6 has a shape along a plane and is formed adjacent to the second convex ridge line portion 4.

The two

square walls

7 and 7 are adjacent to the two

side walls

5 and 5 and the end wall 6, respectively, and in plan view (that is, viewed from a direction orthogonal to the first direction d1 and the second direction d2). ) Curved and formed. Moreover, the two

square walls

7 and 7 are adjacent to the boundary area | region of the 1st convex ridgeline part 3 and the 2nd convex ridgeline part 4, respectively. The concave ridge line portion 8 is formed adjacent to the two

side walls

5, 5, the end wall 6, and the two

square walls

7, 7. Further, the outward flange 9 is formed adjacent to the concave ridge line portion 8.

In FIG. 1, the vicinity of the end 2a in the first direction d1 of the top plate 2 is extracted and shown, but as shown in FIG. 2, another end 2b of the top 2 in the first direction d1. Moreover, the 2nd convex ridgeline part 4, the end wall 6, the

square walls

7 and 7, the concave ridgeline part 8, and the outward flange 9 may be formed. That is, the end wall 6 may be formed only at one end of the top plate portion 2 or may be formed at both ends of the top plate portion 2.
Moreover, although illustration is abbreviate | omitted, the top-plate part 2 may be T-shaped or Y-shaped, and the end wall should just be formed in one or more edge parts of the top-plate part 2 in that case.

In the drawn body 1, the curvature radius Rpl 2 of the cross section orthogonal to the extending direction of each of the two first convex

ridge line portions

3, 3, the curvature radius Rps 2 of the cross section orthogonal to the extending direction of the second convex ridge line portion 4, And the curvature radius Rd2 of the cross section orthogonal to the extending direction of the concave ridgeline part 8 is 30 mm or less, and it is possible to obtain high bending rigidity and torsional rigidity.
The curvature radius Rpl2, the curvature radius Rps2, and the curvature radius Rd2 are all preferably 20 mm or less, and more preferably 10 mm or less.

In the drawn body 1, the first direction d 1 and the second direction d 2 are orthogonal to each other at a position spaced 1.0 mm along the

square walls

7, 7 from the boundary between the outward flange 9 and the concave ridge line portion 8. The corner radius Rpc2, which is the radius of curvature of the

corner walls

7, 7 as viewed from the direction, is 30 mm or less, and this makes it possible to obtain high bending rigidity and torsional rigidity.
The corner radius Rpc2 is preferably 20 mm or less, and more preferably 10 mm or less.

Furthermore, the molding depth h2 which is the separation distance between the top plate 2 and the outward flange 9 in the direction perpendicular to the top plate 2 is 40 mm or more, thereby obtaining high bending rigidity and torsional rigidity. It is possible.
The molding depth h2 is preferably 50 mm or more, and more preferably 70 mm or more.

Conventionally, when a member having a tensile strength of 980 MPa or more and a U-shaped cross-sectional shape or a rectangular cross-sectional shape is to be press-formed with a forming depth of 40 mm or more, the curvature radius Rpl2, the curvature radius It is difficult to reduce Rps2, the radius of curvature Rd2, and the corner radius Rpc2, and even if it can be formed, it has been difficult to exhibit high rigidity due to wrinkles generated in the side wall portion and the like.
In the drawing body 1 according to the present embodiment, by using a manufacturing method and a manufacturing apparatus described later, even if the molding depth h2 is 40 mm or more, the generation of wrinkles on the end walls and side walls is suppressed. However, it is possible to obtain a desired curvature radius and corner radius.
When the forming depth is 100 mm or more, it is difficult to set the curvature radius Rpl2, the curvature radius Rps2, the curvature radius Rd2, and the corner radius Rpc2 to the forming depth h × 0.3 mm or less.

The drawn molded body 1 has an end wall 6 formed at the outermost end portion 2a in the first direction d1, so that the end wall 6, the

square walls

7, 7, the concave ridge line portion 8, It has a U-shaped cross section formed by the outward flange 9 or a rectangular cross section. Therefore, high bending rigidity and torsional rigidity can be exhibited while being lightweight. Therefore, since the drawn molded body 1 can exhibit high collision resistance, it can be suitably used for an automobile structural member such as a side sill, a bumper beam, an A pillar lower panel, an A pillar, or a B pillar.

3A to 3C are explanatory views schematically showing the case where the drawn molded body 1 is used as a side sill.
FIG. 3A is an explanatory view showing a state before the drawn body 1 as a side sill is joined to the A pillar lower panel 10.
3B and 3C are explanatory views showing a first example and a second example of a mode in which the drawn molded body 1 as a side sill is joined to the A pillar lower panel 10.

As shown in FIG. 3A, the drawn molded body 1 as a side sill has a U-shaped cross-sectional shape by being constituted by an end wall 6, a square wall 7, a concave ridge line portion 8, and an outward flange 9.

For this reason, as in the first example shown in FIG. 3B, the longest end portion 2a in the longitudinal direction of the drawn molded body 1 as a side sill is abutted against the inner surface 10a of the A pillar lower panel 10, and further the outermost end portion 2a and the inner surface. By welding 10a, the rigidity of the joined body of the drawn molded body 1 as the side sill and the A pillar lower panel 10 can be increased, and the bending rigidity and torsion of the engine compartment can be increased via the A pillar lower panel 10 and the dash panel. Stiffness can be increased.

Further, as in the first example shown in FIG. 3B, the longitudinal end 2a of the drawn molded body 1 as a side sill is arranged apart from each other without abutting against the inner surface 10a of the A pillar lower panel 10. Is also possible. For example, as in the second example shown in FIG. 3C, the outward flange 9 is overlapped with the outward flange 10b of the A pillar lower panel 10 and welded, so that the drawn body 1 as the side sill and the A pillar lower panel are welded. 10 and the bending rigidity and torsional rigidity of the engine compartment can be increased via the A pillar lower panel 10 and the dash panel.

(2. Apparatus for producing a drawn product for automobile structural member according to one embodiment of the present invention)
The manufacturing apparatus according to the present embodiment is a manufacturing apparatus for the drawn body 1 and includes a first die, a first punch and a first blank holder, a second die, a second punch, a second blank holder, and a tightening tool. .

(2-1. First die, first punch and first blank holder)
FIG. 4 is an explanatory view showing a first intermediate drawing body 11 formed by a first molding die including a first die, a first punch, and a first blank holder. FIG. 4 shows the shape of the first intermediate drawn article 11 up to the middle in the first direction d1, and the remaining shapes are omitted.

The first die, the first punch, and the first blank holder produce a first intermediate drawn article 11 by performing press working by drawing a blank having a tensile strength of 980 MPa or more or a preform thereof.

As shown in FIG. 4, the first intermediate drawn body 11 includes an intermediate top plate portion 12, two intermediate first convex ridge line portions 13, an intermediate second convex ridge line portion 14, two intermediate side walls 15, and an intermediate end wall 16. It is constituted by two intermediate corner walls 17, an intermediate concave ridge line portion 18, and an intermediate outward flange 19.

The intermediate top plate portion 12 has a substantially planar shape and extends in the first direction d1 indicated by a double arrow in FIG. The two intermediate first convex

ridge line portions

13 and 13 are in the second direction d2 (the direction indicated by the double-headed arrow in FIG. 4, which is the width direction of the intermediate top plate portion 12, and perpendicular to the first direction d1 and It is formed continuously on both sides in the direction along the plate portion 12).

The intermediate second convex ridge line portion 14 is adjacent to the outermost end portion 12a of the intermediate top plate portion 12 in the first direction d1, and is formed continuously with the two intermediate first convex

ridge line portions

13 and 13. The two

intermediate side walls

15 and 15 are formed adjacent to the two intermediate first convex

ridge line portions

13 and 13, respectively. The intermediate end wall 16 is formed adjacent to the intermediate second convex ridge line portion 14.

The two

intermediate corner walls

17 and 17 are adjacent to the two

intermediate side walls

15 and 15 and the intermediate end wall 16, respectively, and in plan view (that is, from a direction orthogonal to the first direction d1 and the second direction d2). (See) curved and formed. The two

intermediate corner walls

17 and 17 are adjacent to the boundary region between the intermediate first convex ridge line portion 13 and the intermediate second convex ridge line portion 14, respectively. The intermediate concave ridge line portion 18 is formed adjacent to the two

intermediate side walls

15, 15, the intermediate end wall 16, and the two

intermediate corner walls

17, 17. Further, the intermediate outward flange 19 is formed adjacent to the intermediate concave ridge line portion 18.

In the first intermediate drawn article 11, the curvature radius Rpl 1 of the cross section orthogonal to the extending direction of each of the two intermediate first convex

ridge line portions

13, 13, and the cross section orthogonal to the extending direction of the intermediate second convex ridge line portion 14. And the curvature radius Rd1 of the cross section perpendicular to the extending direction of the intermediate concave ridge line portion 18 are respectively in the extending direction of the two first convex

ridge line portions

3 and 3 of the drawn molded body 1. The curvature radius Rpl2 of the cross section orthogonal to the cross section, the curvature radius Rps2 of the cross section orthogonal to the extending direction of the second convex ridge line portion 4, and the curvature radius Rd2 of the cross section orthogonal to the extending direction of the concave ridge line portion 8 are larger.

The radius of curvature Rpl1, the radius of curvature Rps1, and the radius of curvature Rd1 of the first intermediate drawn body 11 are 1.2 to 30 times the radius of curvature Rpl2, the radius of curvature Rps2, and the radius of curvature Rd2 of the drawn body 1, respectively. It is desirable to form without causing cracks and wrinkles in the first step and the second step.

Intermediate angle seen from the direction perpendicular to the first direction d1 and the second direction d2 at a position spaced 1.0 mm along the

intermediate angle walls

17 and 17 from the boundary between the intermediate outward flange 19 and the intermediate concave ridge line portion 18. An intermediate corner radius Rpc1 that is the radius of curvature of the

walls

17 and 17 is larger than the corner radius Rpc2 of the drawn body 1. The intermediate corner radius Rpc1 is desirably 1.2 to 30 times the corner radius Rpc2 in order to form without causing cracks or wrinkles in the first step and the second step. The intermediate corner radius Rpc1 is more preferably 1.7 to 2.5 times the corner radius Rpc2.

Further, an intermediate molding depth h1 that is a separation distance between the intermediate top plate portion 12 and the intermediate outward flange 19 in a direction perpendicular to the intermediate top plate portion 12 is larger than the molding depth h2 of the drawn molded body 1. The intermediate molding depth h1 is preferably 1.1 to 2.0 times the molding depth h2, in order to perform molding without causing cracks or wrinkles in the second step.
The intermediate molding depth h1 is more preferably 1.2 to 1.5 times the molding depth h2.

(2-2. Second die, second punch and second blank holder)
FIGS. 5A to 5C show that the second intermediate drawing body is converted from the first intermediate drawing body using the second die 21, the second punch 22, the second molding die including the second blank holder 23 and the cam 24. FIG. 5 is an explanatory view showing a first stage to a third stage until a drawn molded body is manufactured. 5A to 5C show the working surfaces of the second die 21, the second punch 22, the second blank holder 23, and the cam 24 for easy understanding of the drawings.

As shown in FIGS. 5A and 5B, the second die 21 accommodates the first intermediate drawn article 11 therein. The second blank holder 23 presses the outer edge portion of the accommodated first intermediate drawn body 11. Further, the second punch 22 moves relative to the second die 21 in the mold clamping direction, thereby pressing the first intermediate drawing body 11 by drawing.

Thereby, the curvature radius Rpl1, the curvature radius Rd1, and the molding depth h1 of the first intermediate molded body 11 shown in FIG. 4 can be reduced, and the curvature radius Rpl2, the curvature radius Rd2, And the 2nd intermediate molded object 31 which has the shaping depth h2 is manufactured.

(2-3. Tightening tool)
In the following description, the case where the cam 24 is used as the tightening tool is taken as an example. However, the tightening tool is not limited to the cam 24, and the intermediate end wall 16 of the second intermediate drawn body 31 is moved in the first direction d1. Any tool that can be pressed to reduce the intermediate corner radius Rpc1 can be used.

When the cam 24 is used as a tightening tool, the cam is a mechanical mechanism that moves the slide of a press machine that moves in the vertical direction to which the second punch 22 and the second blank holder 23 and, in some cases, the second die 21 are attached. It is movable by being converted into a lateral movement through the

When using a device other than the cam, a plate attached to a hydraulic device or an electric device that operates independently from the slide of the press machine may be used.

Next, as shown in FIG. 5C, the cam 24 is in a state in which the second die 21, the second punch 22, and the second blank holder 23 constrain the second intermediate draw-formed body 31. The intermediate end wall 16 is pressed in the first direction d1 to reduce the intermediate corner radius Rpc1 and the curvature radius Rps1, thereby obtaining the corner radius Rpc2 and the curvature radius Rps2 of the drawn molded body 1.

At this time, an inner pad 25 that moves in a direction different from the pressing direction is incorporated in the second punch 22, thereby pressing the inner surface of the intermediate end wall 16 of the second intermediate drawn body 31 and occurring in the intermediate end wall 16. Wrinkles can be suppressed.

FIG. 6 is a top view cross-sectional view showing the molding situation over time when the cam 24 is disposed outside the second die 21.
FIG. 7 is a cross-sectional side view showing the molding situation over time when the cam 24 is disposed outside the second die 21.
FIG. 8 is an explanatory view showing the molding situation over time when the cam 24 is arranged in the second die 21.

As shown in FIGS. 6 and 7, the cam (tightening tool) may be arranged outside the second die 21 so as to be movable in the first direction d1, or as shown in FIG. The two dies may be arranged so as to be movable in the first direction d1 from the outside to the inside.

(3. Manufacturing method of drawing body for automobile structural member according to one embodiment of the present invention)
In the manufacturing method according to the present embodiment, the drawn article 1 is manufactured through the following first to third steps.
First step: A blank having a tensile strength of 980 MPa or more is subjected to press working by drawing using a first die, a first punch and a first holder to form a first intermediate drawn article 11 shown in FIG.
Second step: As shown in FIGS. 5A and 5B, the first intermediate draw-formed body 11 is subjected to press molding using the second die 21, the second punch 22, and the second blank holder 23, and the second intermediate The drawn compact 31 is manufactured.
Third step: As shown in FIG. 5C, the second intermediate drawn body 31 is clamped by the cam 24 while the second intermediate drawn body 31 is restrained by the second die 21, the second punch 22 and the second blank holder 23. The intermediate end wall 16 is pressed in the first direction d1 to reduce the intermediate corner radius Rpc1 and the curvature radius Rps1, thereby obtaining the corner radius Rpc2 and the curvature radius Rps2 of the drawn molded body 1.

In addition, you may excise the press part by the 2nd blank holder 23 of the draw-formed body 1 as needed after a 3rd process.

(Example)
Press-formed bodies 40 to 46 shown in FIGS. 9A to 9G were formed using a 1180 MPa class high-tensile steel plate having a plate thickness of 1.0 mm.
The press-molded body 40 shown in FIG. 9A is a molded body manufactured by a conventional bending method, and has a structure that does not have an end wall.
The press-formed bodies 41 to 46 shown in FIGS. 9B to 9G are formed bodies produced by the drawing method shown in FIGS. 5A to 5C, and have a structure having an end wall at one end.

In the press-formed body 40 shown in FIG. 9A, the curvature radius Rx of the convex ridge line portion is set to 5 mm.
In the press-formed bodies 41 to 46 shown in FIGS. 9B to 9G, the curvature radii Rx of the convex ridge lines are 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm, respectively.

As shown in FIGS. 9A to 9G, a resistance spot is formed by using a high strength steel plate having a plate thickness of 1.0 mm and a tensile strength of 1180 MPa class as a back plate 50 (closing plate) with respect to the flanges of the respective press-formed bodies 40 to 46. Specimens A to G were prepared by attaching by welding. 9A to 9G, the spot indicated by the black circle is a spot weld, the weld pitch is 30 mm, and the weld diameter is 3.3 mm.

FIG. 10 is an explanatory view showing the measurement conditions of torsional rigidity with respect to the device under test A, and the unit of dimension is mm.
As shown in FIG. 10, one end of the test object A is completely restrained including the back plate 50, and the colored region in FIG. And torsional rigidity was investigated.
Similarly, the torsional rigidity of the test pieces B to G was examined, and 1.5 deg. The moments generated during rotation are summarized in the graph of FIG.

As shown in the graph of FIG. 11, the torsional rigidity of the test objects B to G having the U-shaped cross-sectional shape is significantly higher than the torsional rigidity of the test object A having the hat-shaped open cross-sectional shape. It can be seen that the torsional rigidity decreases when the curvature radius Rx of the convex ridge line portion exceeds 30 mm as in the test bodies F and G.

Further, the bending stiffness was measured using the specimens A to G prepared as described above.
FIG. 12 is an explanatory view showing the measurement conditions of the bending rigidity for the test object A, and the unit of the dimension is mm.
As shown in FIG. 12, the bending rigidity was examined by applying displacement to the colored region of FIG.
The bending stiffness is similarly examined for the test objects B to G, and the bending load when each 1.5 mm displacement is applied is collectively shown in the graph of FIG.

As shown in the graph of FIG. 13, the bending rigidity of the test objects B to G having a U-shaped cross-sectional shape is significantly higher than the bending rigidity of the test object A having a hat-shaped open cross-sectional shape. It can be seen that when the radius of curvature Rx of the convex ridge line portion exceeds 30 mm as in the test bodies F and G, the bending rigidity decreases.

As a comparative example, a press-molded body having the same dimensions as the press-molded body 41 shown in FIG. 9B was produced by drawing without operating the inner pad 25 shown in FIGS. 5A to 5C. Remarkable wrinkles occurred on the walls. A specimen to be tested was prepared from the press-molded body in the same manner as described above, and the torsional rigidity and bending rigidity were measured in the same manner as described above. The moment generated during rotation was 600 N · m, and the bending load when applying a displacement of 1.5 mm was 5.1 kN. It was confirmed that high torsional rigidity and bending rigidity could not be exhibited.

ADVANTAGE OF THE INVENTION According to the present invention, an automotive structural member drawing molded body, a method for manufacturing an automotive structural member drawing molded body, and an automotive structural member drawing that can improve the collision resistance characteristics by increasing the rigidity while realizing weight reduction. An apparatus for manufacturing a molded body can be provided.

DESCRIPTION OF SYMBOLS 1 Drawing body 2 for automotive structural members Top plate part 3 First convex ridge line part 4 Second convex ridge line part 5 Side wall 6 End wall 7 Square wall 8 Concave ridge line part 9 Outward flange

Claims

A drawn molded body for automobile structural members having a tensile strength of 980 MPa or more,
A top plate extending in the first direction;
Among the top plate portions, two first convex ridge line portions that are orthogonal to the first direction and are adjacent to both sides in the second direction along the top plate portion;
A second convex ridge line portion adjacent to the outermost end portion of the first direction of the top plate portion and continuing to the two first convex ridge line portions;
Two side walls adjacent to the two first convex ridge lines,
An end wall adjacent to the second convex ridge line portion;
The two side walls, and two square walls adjacent to the end wall and having a curved shape when viewed from a direction orthogonal to the first direction and the second direction;
A concave ridge line adjacent to the two side walls, the end wall and the two corner walls;
An outward flange adjacent to the concave ridge line portion;
With
The two first convex ridge line parts, the second convex ridge line part and the concave ridge line part each have a radius of curvature of a cross section perpendicular to the extending direction of 30 mm or less,
The radius of curvature of the square wall as viewed from the direction perpendicular to the first direction and the second direction at a position spaced 1.0 mm along the square wall from the boundary between the outward flange and the concave ridge line portion. A corner radius is 30 mm or less,
A drawing molded body for automobile structural members, wherein a molding depth, which is a distance between the top plate portion and the outward flange, in a direction perpendicular to the top plate portion is 40 mm or more.
2. The drawn article for an automobile structural member according to claim 1, wherein the end wall, the two square walls, the concave ridge line portion, and the outward flange are formed at both ends in the first direction.
3. The drawn article for automobile structural members according to claim 1, wherein the drawn article is a side sill, a bumper beam, an A pillar lower panel, an A pillar, or a B pillar.
A method for producing a drawn article for an automobile structural member according to any one of claims 1 to 3,
An intermediate top plate portion extending in the first direction by performing press working by drawing using a first die, a first punch and a first blank holder on a blank having a tensile strength of 980 MPa or more, and the intermediate top plate portion Among the two intermediate first convex ridge lines adjacent to both sides of the second direction orthogonal to the first direction, and the two intermediate first adjacent to the extreme end of the intermediate top plate in the first direction. An intermediate second convex ridge line portion continuous with one convex ridge line portion; two intermediate side walls continuous with the two intermediate first convex ridge line portions; an intermediate end wall adjacent to the intermediate second convex ridge line portion; Two intermediate side walls, two intermediate corner walls adjacent to the intermediate end wall and having a curved shape when viewed from a direction orthogonal to the first direction and the second direction, and the two intermediate side walls, Intermediate end wall and the two intermediate angle walls An intermediate intermediate ridge line portion adjacent to the intermediate concave ridge line portion and an intermediate outward flange adjacent to the intermediate concave ridge line portion, the two intermediate first convex ridge line portions, the intermediate second convex ridge line portion, and the intermediate concave ridge line portion, The radius of curvature of the cross section orthogonal to the extending direction of each of the two is orthogonal to the extending direction of each of the two first convex ridge line portions, the second convex ridge line portion, and the concave ridge line portion of the drawn molded body. It is larger than the radius of curvature of the cross section and is orthogonal to the first direction and the second direction at a position spaced 1.0 mm along the intermediate angle wall from the boundary between the intermediate outward flange and the intermediate concave ridge line portion. The intermediate top plate portion in a direction perpendicular to the intermediate top plate portion, wherein the intermediate corner radius, which is the radius of curvature of the intermediate square wall as viewed from the direction in which it is viewed, is larger than the corner radius of the corner wall of the drawn molded body And said intermediate outward A first step of intermediate molded depth for forming the first intermediate aperture formed body greater than the forming height of the drawing which is a distance between the flanges,
The first intermediate drawn body is pressed by drawing using a second die, a second punch, and a second blank holder, the two intermediate first convex ridge lines, the intermediate second convex ridge lines, and The two first convex ridge lines and the second convex ridge lines of the drawn molded body can be obtained by reducing the curvature radius of the cross section orthogonal to the extending direction of each of the intermediate concave ridge lines and the intermediate molding depth. A second step of forming a second intermediate drawn article having a radius of curvature of the cross section perpendicular to each extending direction of the part and the concave ridge line part and the forming depth;
The second intermediate draw-formed body is restrained by the second die, the second punch, and the second blank holder, and the first intermediate draw-formed body is formed by an inner pad built in the second punch. A third step of reducing the intermediate corner radius of the intermediate angular wall by pressing the intermediate end wall of the second intermediate drawn molded body in the first direction with a tightening tool while pressing the inner surface of the intermediate end wall;
A method for producing a drawn article for an automotive structural member.
The intermediate molding depth is 1.1 to 2.0 times the molding depth,
The radius of curvature of each of the two intermediate first convex ridge line portions, the intermediate second convex ridge line portion, and the intermediate concave ridge line portion is any of the two first convex ridge line portions, the second convex ridge line portion, and the concave portion. 1.2 to 30 times the radius of curvature of each ridge part,
The method of manufacturing a drawn article for an automobile structural member according to claim 4, wherein the intermediate corner radius is 1.2 to 30 times the corner radius.
6. The method of manufacturing a drawn article for an automobile structural member according to claim 4, wherein the tightening tool is arranged to be movable in the first direction outside the second die.
The said tightening tool is arrange | positioned so that a movement to said 1st direction is possible from the exterior to the inside of said 2nd die | dye, The manufacturing method of the drawing molded object for motor vehicle structural members of Claim 4 or 5 characterized by the above-mentioned.
An apparatus for manufacturing a drawn molded body for automobile structural members according to any one of claims 1 to 3,
A first mold having a first die, a first punch, and a first blank holder;
A second molding die having a second die, a second punch, and a second blank holder;
A tightening tool;
With
The first molding die is orthogonal to the first direction among the intermediate top plate portion and the intermediate top plate portion extending in the first direction by performing press working by drawing on a blank having a tensile strength of 980 MPa or more. Two intermediate first convex ridge line portions adjacent to both sides in the second direction, and an intermediate portion adjacent to the outermost end portion in the first direction of the intermediate top plate portion and continuing to the two intermediate first convex ridge line portions. A second convex ridge line portion, two intermediate side walls continuous to the two intermediate first convex ridge line portions, an intermediate end wall adjacent to the intermediate second convex ridge line portion, the two intermediate side walls, and the intermediate Two intermediate corner walls that are adjacent to the end wall and have a curved shape when viewed from the direction orthogonal to the first direction and the second direction, the two intermediate side walls, the intermediate end wall, and the two intermediate points An intermediate concave ridge line adjacent to the corner wall and the intermediate An intermediate outward flange adjacent to the ridge line portion, and the two intermediate first convex ridge line portions, the intermediate second convex ridge line portion, and the intermediate concave ridge line portion have a radius of curvature of a cross section orthogonal to the extending direction thereof. Are both larger than the radius of curvature of the cross section perpendicular to the extending direction of each of the two first convex ridge line portions, the second convex ridge line portion, and the concave ridge line portion of the drawn molded body, The radius of curvature of the intermediate angle wall as viewed from the direction perpendicular to the first direction and the second direction at a position spaced 1.0 mm along the intermediate angle wall from the boundary between the orientation flange and the intermediate concave ridge line portion The intermediate corner radius is larger than the corner radius of the corner wall of the drawn molded body and is a separation distance between the intermediate top plate portion and the intermediate outward flange in a direction perpendicular to the intermediate top plate portion. An intermediate Depth molding the first intermediate aperture formed body greater than the forming height of the draw-forming body,
The second molding die performs press molding by drawing on the first intermediate drawn body, and each of the two intermediate first convex ridge line parts, the intermediate second convex ridge line part, and the intermediate concave ridge line part, By reducing the radius of curvature of the cross section perpendicular to the extending direction of and the intermediate molding depth, the two first convex ridge line portions, the second convex ridge line portions, and the concave ridge line portions of the drawn molded body, Forming a second intermediate drawn article having a radius of curvature of the cross section perpendicular to each extending direction and the forming depth;
The tightening tool is formed in a state in which the second intermediate drawing body is constrained by the second molding die and the intermediate end wall of the first intermediate drawing body is formed by an inner pad built in the second punch. A drawing forming body for an automobile structural member, wherein the intermediate corner radius of the intermediate corner wall is reduced by pressing an intermediate end wall of the second intermediate drawing forming body in the first direction while pressing an inner surface. Manufacturing equipment.
The intermediate molding depth is 1.1 to 2.0 times the molding depth,
The curvature radii of the two intermediate first convex ridge line parts, the intermediate second convex ridge line part, and the intermediate concave ridge line part are respectively the two first convex ridge line parts, the second convex ridge line part, and the concave ridge line part. 1.2 to 30 times the radius of curvature of
9. The apparatus for manufacturing a drawn article for automobile structural members according to claim 8, wherein the intermediate corner radius is 1.2 to 30 times the corner radius.
10. The apparatus for manufacturing a drawn member for an automobile structural member according to claim 8, wherein the tightening tool is arranged to be movable in the first direction outside the second die.
10. The apparatus for manufacturing a drawn member for an automobile structural member according to claim 8, wherein the tightening tool is disposed so as to be movable in the first direction from the outside to the inside of the second die.